Ore-roaster.



G. H. DERN & T. P. HGLT.

ORB ROASTER. APPLICATION FILED APR. 9. 1914.

1,113,961. Patented o@1;.2o,1914.

In l l Serf 9.

UNITED sTATEs PATENT GEORGE H. DERN, or SALT LAKE CITY, AND THEoDoE'E P'. Hom', or PARE CITY, UTAH.

' ORE-Rowman.

Specica-tion of Letters Patent.

Patented Oct. 20, 1914.

i Application mea April s, 1914. serial No. ssoe'e'a.

T0 all whom it may concern:

Be it known that we, GEORGE H. DERN and THEODORE P. HoLT, citizens of the United States, residing, respectively, at Salt Lake City, county of Salt Lake, State of Utah, and Park City, county of Summlt, State of Utah, have invented certain new and useful Improvements in Ore-Roasters, of which the following is a specification.

This invention relates to blast ore roasters. 1 f

Our object is the provision of a novel ore roaster adapted for carrying out the roast ing process set forth in the appllcatlon of Neils C. Christensen, Jr., and Theodore l?.v Holt, filed August 3, 1911, Serial No.3 642,088 and that set forth in the patent to.

Wilhelm Buddeus No. 1,079,897, .dated November 25, '1913; and still further, adapted for the performance of a blast roasting.

process embodying improvements .on .the roasting process of the said application and patent.

Our invention is adaptedvfor the treat.

ment of any metal bearing ore, particularly those ores which require an oxldizmg or chloridizing roast preparatory to the extraction of the valuable metals by any sult- L nent but shifting roastiagfy zone 1n the columnar charge of ore and removes the able solvent.

The invention relates, more particularly to the provision of a novel blastl roaster adapted for the treatment .of ores'which are, first finely crushed and moistened and (if not carrying the necessary fuel themselves) are mixed with suflicient fuel to adapt themV for roasting by internal combustion ofthe mass, by forcing a blast `of air through the; charge and for the treatment of the charge.

in a novel manner.

roasting is from ten to fteen per cent., is

practically eliminated; a saving ofv about seventy-five per cent. of the fuel. consumed by other roasters is effected; the cost of 1nstallation is greatly minimized; the fumesl are concentrated and, when desired, may-be easily condensed; the roasted product Is free from slime :and conse uently much.

easier to leach; and dusting,w1thitsconsid erable loss, is entirely eliminated.

Our ore roaster is continuous in operation to the extent that the fire is never allowed to go out and the roaster is never completely emptied, although it is charged and discharged intermittently; further, the roasting zone is allowed to travel upward until it reaches the top of the charge, or substantially so, whereupon it is droppedsuddenly, after which it can again travel tothe top. A desideratum in roasting ore by our process'is to obviate the occurrenceof portions or sections" of the charge which offer less resistance than the remaining portions thereof, because suchweak places permit a rush of air through them and thusthe orecausedit to settle away from the walls of the' .roaster, thereby' forming air channels.

-The present `roaster is adapted to cause they charge to drop quickly and'freely" at desi-red Intervals, and Vwhile cracks may occur, they .may be sealed up with a layer offresh ore and cause no difference in roasting.

The present roaster maintains a ermaroasted ore from beneath the roasting zone at .inter-vals, yfresh unroasted ore being addedon top as required.

Our invention consists,- first, of an open' charge-supporting and air distributing .grate,va charge-holding or roasting chamber, andan `equalizing air pressure box or chamber, relatively arranged lso :that `the blast from said air box or chamber has free 1access .to' the charge being roasted and is" subject-to air pressure control at will';;sec ond, a preferred .embodiment of said elements, in' which the charge-holding -and roastin chamber is uppermost, yand the -equalizmgfair pressure box or chamber isl .arranged .therebelow, an f open charge-suppbrting, crushing and blast distributin grate being. ylocated between the said cham-v b rs, theair pressure box or chamber being nbrmallyfree from contained Toasted ore, or substantially so, but I alsov incidentallyservingas a hopper'forthe-temporary hold-v- .a g. of such `yportion of the charge asis intermittently `crushed and lowered by the grate, until the discharged roasted ore may lbe removed third, a novel open charge-supporting crushing grate having relatively movable sections or parts, which preferably travel in opposite directions, 'together with operating means therefor, said grate being so constructed and related to the walls of the-.roasting chamber that it is adapted to crush or scrape off the bottom of the roasted ore cake and discharge the broken and roasted ore through and beneath the grate without disastrous pressure on the walls of the roaster and at the same time, insuring a uniform settlement of the roasting charge; fourth, a roasting chamber whoseinternal size increases toward its lower part where it approaches the grate, which construction prevents the charge from adhering to the side walls and thus insures an even settling through Athe ore mass when the grate` is operated.

The invention also consists in a particular improved grate for an ore4 roaster; improved means for supporting the grate; the relationship of the said grate to the walls of the upper charge-holding chamber and the lower equalizing air pressure box; and the provision ofl controlling means f or the roastlng chamber, whereby the fumes may be taken off, as desired, to a stack or condenser.

The embodiment of the invention -disclosed in the drawings and hereinafter described is, in the broader aspect thereof,

capable of modification within the spirit and scope of the invention and, except where limited in the appended claims, is to be deemed as illustrative, rather than restrictive, of the scope of the invention. In the accompanying drawings: Figure 1 is a vertical'section through the center -of the roaster on the line 1-1, Fig. 2; Fig. 2, a plan view, the cover beingremoved; Fig. 3, a detail section on the line 3 3, Fig. 1, and Fig. 4, a cross section on line 4 4, Fig. 1.

The body 1 of the roaster is preferably square or rectangular in cross section, havling an air box or chamber 2. The roaster iss supported by horizontal members 3 carried by posts 4 resting on a suitable foundation. The upper part ofthe shell has a suitable refractory lining 5 to conserve the heat and protect'the shell 1 from corrosive gases. A removable or hinged cover 6 is provided 'for the normal closure of the roaster and the admission of the ore. A iiue 7 connects the r roaster 'witha smoke-stack, or condensing The ate is composed of a plurality of relative y reciprocatable sections 8 composed of bars 8a and transverse grate bars 8b which' A areconnected to and supported by the bars '85l and are provided on .their upper edges with serrations, teeth, or projections 8, Fig.

3. The bars 8a and 8b may be connected together in any preferred manner. In each grate section 8, the bars 8 are parallel to each other and the transverse bars y8b are parallel.

Referring to Fig. 3, to the bars 8?, which may be angle-iron, are secured guards 11 extending, in each instance, substantially the width of the given grate section 8. The ends of the guards are downwardly disposed, preferably inclined, as shown in Fig. 1.

Extending crossw-ise of the roaster are stationary channel irons* 10 to which are secured, at intervals of the length thereof, roller supporting blocks 10a which are of more or less dished configuration .on their upper faces and are provided with upwardly extending parts 10b.

Resting on a lurality of the roller supports 10a are rollers 9 which are preferably provided with heads on their ends 9a so that they are retained against displacement from the supports 10a. The guards 11, of which there are two for each grate section 8, rest -upon the two rollers 9 provided for that section. Thus, each section 8 of the grate is mounted independently of all other sections thereof. F'or convenience, however, the channel beams 10 are employed for supporting all of the roller supports 10.

The crushing grate sections 8 may be reg ciprocated in any preferred manner, but we preferably operate them from the same shaft 14 which is suitably `mounted in bearings on the frame 3, by cranks-or eccentrics 14 connected to rods' 12 on the grate sections by links 13a, said rods 12 working through stuffing boxes 13 in the shell 1. Preferably, thelinks 13a and their rods are set so that contiguous .sections 8 of the grate travel in opposite directions in relation to each other. We do not limit ourselves, however, to this construction and operation of the grate, except where specified in the claims. The advantage gained byl this opposite travel of the grate sections is that 1t distributes the y,crushing strain transmitted through the orc to the roaster shell, whereas if all of the grate sections traveled as a unit, the opposite sides of th`e shell would be alternately subjected to` relatively great pressure. Also, if all thegrate sections traveled as a unit they would have a tendency to carry the entire charge bodily back and forth, thereby forming-air channels along the sides of the shell. rlhe shaft 14 may be driven in any suitable manner, as for instance, by gearing 15, 16, from a shaft 16 having pul- -iey 16h.

A pipe for delivering the air blast to air box 2 is shown at 17, the latter having perforations oi' an elongated slot 17 on its lower side, the nozzle portion of said pipe extend into the box 2.

arrasar being disposed crosswise of the hopper bottom 2 below the grate. A valve 18y controls the air blast. An air-tight door20 is ro-A We consider it advisable to provide a smooth interior for the lining 5 and that. it'be of som what greater internal size to.-l

ward its lower part where it approaches the grate, in order that an even settlement of the charge will occur. Finely divided ore, properly moistened, cakes together in roasting, and by providing the foregoingv features, theore mass may be lowered without disturbing the roasting ore particles in their relation to each other, whereas if the internal size of the roaster is the same from top to bottom or is smaller at thelbottom, the charge is liable to hang up, by adherin `to the sides, thus necessitating hand wor in relieving this condition. The open construction of thegrates permits scraped or broken off parts of the ore cake to drop freely from them. The ends of the gratev are overhung by the lower end 5a of the lining 5. This prevents thev ore from getting between the ends of the grate and the wall 5 and prevents breakage due t'o the crushing action which would otherwise occur at these points. Furthermore, the open grate construction insures an even distribution of the air blast to the charge. The shield bearings 11 prevent dust and ore vfrom having access to the lower bearing members 10a and prevent vclogging of the rollers 9. At the same time, the spacing apart of vthe bear ing members 10a, permits the nmaterial vto drop through without accumulation. The air box 2 provides a free air-distributing chamber from which the air blast has access to all parts of the grate and. through/ but the following has been found in practice] to give the best results. The grate sections 8 are rst covered with a layer of roasted ore lumps of such size that they will not fall through. Three or vfour inches of line ore is then spread over the said roasted ore lumps to insure an even distribution of the air. A layer of smallpieces of wood to the depth of two or three inches is then placed on the line ore. Kerosene may be sprinkled over the wood. Upon igniting the wood, a quick spreading of the ame over the entire surface occurs, the air blast being meanwhile regulated by the valve 18. After the wood is burned to coals the rst char e of suitably prepared ore'is put on. The uel in the ore becomes ignited and the mass begins to roast, the roasting zone proceeding upward. The cover 6, which has been thrown back up to this time, is now closed, s o that: the'smoke andy gases pass out throughflue 7 to a condensing chamber or toy a chimney. At intervals the cover is raised and additional charges vof. creare added, until the roaster v is filled. The roasting Zone meanwhile is `ascending-and finally approaches the top of the roaster, say, to a point about level with the bottom of the Hue 7 whereupon the air blast is shut of by closing the valve 187 and' A the .charge is lowered. Up to the timeof lowering the charge, the grate sections 8 are `allowed to remain stationary, but when the charge is to be lowered, power is applied to reciprocate the grate sections 8. The teeth, projections,for serrations 8 scratch or s crape'andcrush or cut 0H the bottom of the roasted calze and the broken o portions of roasted ore fall through the open crush ing grate sections 8 into the hopper 2.

The mounting of the grate sections on the-rollers, reduces friction and the grate sections require but little power for their reciprocation, as they roll easily on the roll` ers 9. When desired, a gate 19 in the bottom of the hopper`2 is opened to discharge the roasted ore into a bin, car, or onto a conveyer or into a launder, as desired.

The charge having been lowered, as described, to the desired distance, and the ore let out of the hopper 2, the gate 19 is closed, the power cut off so that the grate sections will remain stationary, and a fresh charge cf ore is delivered into the roaster. The cover 6 is then closed and the valve 18 opened, and the roasting loperation is resumed until the roasting zone,l by its ascension, finally reaches the desired point where it is advisable to again drop the charge.

In our roaster, the heated air and gases travel in on opposite direction to the ore-and it will be seen', therefore, thattheroaster applies the principle of counter currents to the process of blast roasting ina most economical manner. It also secures an intimate contact between the active gases of the roast .and the mineral particles of the ore so as toproducethe desired reaction with a minimum of reagents. In the old types of roastin '.furnaces, the loss of valuable metals exceeds ten per cent. of the total value of the ore. We have demonstrated on a commercial scale that .there is practically no loss of valuable metals when roasted in our roaster and thatV the gases are entirely free from dust, comparatively cool, and conceny volatilization and dusting often,

trated, and can easily be condensed fon leachingv purposes; further, that the roasted ore is practically free .from slime and is brought to a pervious character which is an t chloridizing roast be prepared, additionalreagents, such as salt, pyrite, etc., are added to the mixture before it is charged into the roaster.

In our roaster we provide means for carrying out the Christensen and Holt and Buddeus roasting processes but, in addition, we carry out a new or improved roasting process by new means. The charge is supported by the grate in our invention, free from contact with any previously roasted ore below the grate. The grate is not embedded in ore above and below it as in the Christensen and Holt and Buddeus processes. rlhe provision of the air or wind box 2 which is never filled with ore, causes the blast to be equalized and also to be distrib* uted to all parts of the grate, the latter be ing constantly subject to the blast, under Whatever control of the latter may be exercised by valve 18. The box 2 also acts as a roasted ore collector but its latter function does not interfere with its service as an air or wind bcX and, in carrying out the process of roasting, we, therefore, not only progress the roasting zone upwardly, as in the Christensen and Holt and Buddeus processes, but, also, support the column of roasting ore while allowing the roasted and scraped 0E ore to freely drop or falll away from the grate and at the same time have a selfequalizing source of air blast.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is

1. In an ore roaster adapted for roasting a single columnar charge by internal combustion thereof, a charge-holding chamber, a crushing grate consisting solely of independent oppositely movable sections each of open form arranged and adapted for directly supporting the single columnar charge in Said chamber and for crushing or disintegrating the ore when said sections are moved, to discharge the disintegrated ore through said grate, means for operating said sections in opposite directions to each other, a combined collecting and air pressure chamber located below said grate and means for introducing a blast of air into said lastnamed chamber and upwardly through said grate into a charge supported thereon for the purpose of roasting the charge solely by internal combustion thereof.

2. In an ore roaster adapted for roasting a single columnar charge by internal combustion thereof, a charge-holding roasting chamber, a crushing grate consisting solely of independent oppositely movable sections each of open form arranged and adapted for directly supporting the single columnar charge in said chamber and for crushing or disintegrating the ore when said sections are moved, to discharge the disintegrated ore through said grate, means for operating said sections in opposite directions to each other, said roasting chamber having walls which overhang the ends of the sections of the grate, whereby access of ore between the ends of the grate sections and the walls of the roasting chamber is prevented, a combined collecting and air pressure chamber located below the grate and means for introducing a blast of air into said last named chamber and upwardly through the grate into a charge of ore supported thereon for the purpose of roasting the charge solely by internal combustion thereof.

3. In an ore roaster adapted for roasting a single columnar charge by internal com bustion thereof, an upper roasting chamber for holding said charge, an air distributing crushing grate composed of independent, movable crushing parts or sections collectively arranged and adapted for directly supporting a` single columnar charge in said chamber, and for crushingA or disintegrating the ore when said sections are moved, to discharge the disintegrated ore through said grate, a combined collecting and air pressure chamber located below said grate, and means for regulably and at will introducing an air blast into said collecting and air pressure chamber.

4.1m an ore roaster adapted for roasting a columnar charge by internal combustion thereof, a charge-holding roasting chamber, a crushing grate having relatively movable crushing sections arranged and adapted for directly supporting the columnar charge in said chamber and for crushing or disintegrating the ore when said sections are moved, to discharge the disintegrated orethrough said grate, roller bearings supporting said grate, guards carried by the grate sections adapted for the protection of the roller bearings, and means for introducing al blast of air upwardly through said grate into a charge supported thereon for the purpose of roasting the charge solely by internal combustion thereof.

5. In an ore rc-aster adapted for roasting a columnar charge by internal combustion thereof, a charge-holding roasting chamber, a crushing grate having relatively movable crushing sections arranged and adapted for directly supporting the columnar charge in said chamber, said sections having grate bars equipped with teeth or projections adapted for crushing or disintegrating the ore when said sections are moved, to discharge the disintegrated ore through said grate, and means for introducing a blast of air upwardly through said grate into a charge supported thereon for the purpose of roasting the charge solely by internal combustion thereof.

. G. An ore roaster having` a Charge-holding roasting chamber, in combination With a grate oomposed'of relativelymovable sections Whose outer parts are overhung by the lower ends of the Wallsof said roastingv chamber, and a combined air pressure and collecting chamber located below said grate.

In testimony whereof, We hereunto aiix our signatures 1n presence of tWo Wltnesses. 15

GEORGE H. DERN. THEODORE P. HOLT.

Witnesses to signature of 'George H. Dern:

A. REEVES, Y

A. L. STERNBURG. Witnesses to signature of Theodore P. Holt:

HENRY FARES, HAROLD J. EVANS. 

